Sunday, January 25

Google App Engine

Abstract :-

Google App Engine was
first released as a beta version in April 2008. It is a platform for developing
and hosting web applications in Google-managed data centers. Google’s App
Engine opens Google’s production to any person in the world at no charge. Much
like Google gives us all free email with an amazing amount of long term storage,
we now have the ability to run the software that we write in Google’s data centers.

Google App Engine is
cloud computing technology. Google App Engine is software that facilitates the
user to run his web applications on Google infrastructure. It is more reliable
because failure of any server will not affect either the performance of the end
user or the service of the Google.

Introduction

Google App Engine
lets you run your web applications on Google's infrastructure. App Engine
applications are easy to build, easy to maintain, and easy to scale as your traffic
and data storage needs grow. With App Engine, there are no servers to maintain:
You just upload your application, and it's ready to serve your users.

You can serve your
app from your own domain name (suc h as http://www.example.com/) using Google
Apps. Or, you can serve your app using a free name on the appspot.com domain.
You can share your application with the world, or limit access to members of
your organization.

Google App Engine
supports apps written in several programming languages. With App Engine's Java
runtime environment, you can build your app using standard Java technologies,
including the JVM, Java servlets, and the Java programming language—or any
other language using a JVM-based interpreter or compiler, such as JavaScript or
Ruby. App Engine also features a dedicated Python runtime environment, which
includes a fast Python interpreter and the Python standard library. The Java
and Python runtime environments are built to ensure that your application runs
quickly, securely, and without interference from other apps on the system.

Working Of Google App Engine

Creating an App
Engine application is easy, and only takes a few minutes. And it's free to
start: upload your app and share it with users right away, at no charge and
with no commitment required.

Google App Engine
applications can be written in either the Java or Python programming languages. The Steps for how to
create an application and deploy on app engine is shown below.

Python Runtime Environment

With App Engine's
Python runtime environment, you can implement your app using the Python
programming language, and run it on an optimized Python interpreter. App Engine
includes rich APIs and tools for Python web application development, including a
feature rich data modeling API, an easy-to-use web application framework, and
tools for managing and accessing your app's data. You can also take advantage
of a wide variety of mature libraries and frameworks for Python web application
development, such as Django.

The Python runtime
environment uses Python version 2.5.2. Additional support for Python 3 is being
considered for a future release. The Python environment includes the Python
standard library. Of course, not all of the library's features can run in the
sandbox environment. For instance, a call to a method that attempts to open a
socket or write to a file will raise an exception. For convenience, several
modules in the standard library whose core features are not supported by the runtime
environment have been disabled, and code that imports them will raise an error.

Application code
written for the Python environment must be written exclusively in Python.
Extensions written in the C language are not supported. The Python environment
provides rich Python APIs for the data store, Google Accounts, URL fetch, and
email services. App Engine also provides a simple Python web application
framework called webapp to make it easy to start building applications.

Billing and Budgeting Resources

Each App Engine
application can consume a certain level of computing resources for free,
controlled by a set of quotas. Developers who want to grow their applications beyond
these free quotas can do so by enabling billing for their application and using
Google Checkout to set a daily resource budget, which will allow for the
purchasing of additional resources if and when they are needed. App Engine will
always be free to get started, and after you've enabled billing for your app
all usage up to the free quotas will remain free.